New tests suggest that radioactive wastes from the Hanford Nuclear Reservation underground tanks may have already reached ground water, and may eventually taint the Columbia River, an expert from the Washington state Department of Ecology said Tuesday.
The statement from Toby Michelena, the department’s chief observer of the tank farm, came after the state agency issued a statement saying it was “concerned” by new testing showing that contamination appears to have moved much farther from the tanks than had been expected.
“We don’t believe that this contamination poses an immediate threat to the public, but long-term risk has escalated,” said the Department of Ecology’s director, Mary Riveland.
The Department of Ecology was responding to an Energy Department disclosure that it had found radioactive cesium-137 at least 125 feet below the surface of the Hanford Nuclear Reservation’s waste tank farm. Ground water is about 200 feet below the surface, state officials said.
New testing also found a plume of radioactive technetium in ground water beneath the SX tank farm at Hanford’s 200 West Area, the state agency said. It noted that federal officials attribute the technetium to the former disposal of wastewater into surface cribs and ponds, rather than to the waste tanks. But officials at the Department of Ecology think some of the contaminant came from the tanks, Michelena said.
Ecology officials said the movement could eventually pollute both ground water and the Columbia River.
Energy Department spokesman Guy Schein said “we share the concern of Ecology” about the new test results. He said the federal agency’s consultants have suggested that the test results might be mistaken, and that new samplings may be needed.
Waters below the Hanford site are hardly pristine. About 2.7 billion cubic meters of ground water under the reservation are known to have been contaminated with chemical and radioactive pollutants from dilute solutions that were dumped into the ground in the 1940s and 1950s. The Energy Department said this pollution was so diluted that it posed little threat to the Columbia River.
The tank farm, in contrast, holds concentrated radioactive waste. About 3.8 million liters or more of this stuff is believed to have leaked into the soil, the Energy Department says.
Riveland said the new test results concerned her because “we have been assured for many years that contaminants from the tanks were trapped in the soils beneath the tanks and were not traveling downward to the ground water.”
“If the cesium is moving downward from the tanks,” Riveland said, “the likelihood of future extensive contamination of ground water beneath the site greatly increases. “We are concerned that radioactive materials from the tanks will eventually reach the Columbia River.”
About 61 million gallons of highly radioactive wastes from the production of plutonium for nuclear weapons are stored in 177 huge tanks on the Hanford Nuclear Reservation near Richland.
Some of the tanks are potentially explosive, and many have leaked their wastes into the environment.
A team from the Energy Department’s Office of Environmental Restoration and Waste Management investigated conditions at the tank farm and reported in 1993 that the condition of the tank farms is poor and continues to deteriorate because corrective maintenance is not keeping up with equipment failure.
About one-third of the instruments on the tanks do not work, and some instruments produce results of “indeterminate quality,” the investigative team said.
The team said it was unlikely that leaks from the older tanks would be immediately detected.